What determines whether a wild animal gracefully ages? New research suggests that environmental conditions during the formative years of an animal can influence the aging process of the animal.
In order to better understand the relationship between adolescence and the twilight years of an animal, researchers from the Australian National University have collected data on 14 different species of birds and mammals, including swallows, storks and kestrels, as well as deer. sheep, mountain goats, squirrels and striped mongoose.
"We investigated the effect in two different types of senescence: reproductive senescence, measured as decreases in reproductive output in the late life phase, and survival encecence, measured as the reduction of the survival rate in late life," Eve Cooper, a Ph. D. student in the department of biology of the ANU, said in a press release.
Although the environmental conditions during the first years of life of an animal did not affect survival later in life, the data showed that animals that enjoyed cuddling during adolescence had a greater reproductive success during their later years.
RELATED Fertile and longevity: termite queen defies the limits of biology
For almost all animals, reproduction rates decrease as they age. But for animals that enjoyed better environmental conditions early, the drop-off was less serious.
Researchers said it is possible that early living conditions also affect survival, but that is too difficult to measure. It is likely that many animals born in poor conditions die before they reach old age, skewing the statistics.
Until recently, many ecologists thought that age was rare in wild animals.
RELATED Study suggests that maki live longer by eating less
"Because we now have a better basis for data on wild animals and what happens to them from birth to death, it is recognized that senescence is very common in wild populations." Cooper said. "What we have also learned from these long-term animal studies is that there is a lot of variation between individuals, so two animals living in the same population may show a dramatic difference in senescence."
Researchers also believed old age was rare in humans, but recent studies have shown that the average age of death was 70 years among many old human populations.
Scientists are still not sure what the variability of senescence explains. Many studies have examined animals for ways to slow down the aging process. But authors of the latest research – published this week in the journal Evolution Letters – find it equally important to understand aging from an evolutionary perspective.
RELATED Study reveals secrets of DNA mutation
"Understanding the evolution of aging in the natural world can actually have fairly broad implications for our understanding of aging in humans," Cooper said.